Interlocking line-circuit railway traffic controlling apparatus



INTERLOCKING LINE-CIRCUIT RAILWAY TRAFFIC CONTROLLING APPARATUS FiledSept. 6, 1945' s Sheets-Sheet 1 ESQ K55 \wmux w a g m A Q Q w 6, l3 w [w0m Om .NN.

m u 3% n 9% \amm www WWW IN VE N TO R. W rezz PK Saz'tz.

B Y Q 1 HIS ATTORNEY mmwbn w. w.' SEITZ April 13, 1948.

. 5 Sheets-Sheet 2 .q/ 5? @r N? 50 #3 a so? go my #8 Q o w v INVENTOR.

ppen W Sez'z. [3)

ugl-

F'iled Sept. 6, 1945 Na NMWE QQQGLW NNN NQQ NW5 g Z g @F. RN 7% g E Rmaw m 3% E 2 E H15 ATTOHNEY W. W. SEITZ April 13, 1948.

Filed Sept. 6, 1945 w Y Ww A i 3H; m n m LM ER a EB T l 5% v i 5 m w .IIFII i 1 L wmw flwww Ru Z 5N5 RM Q Ev Patented Apr. 13, 1948 CIRCUITRAILWAY TR'AFFIC'GONTROLEINGFMPARAIEUS fiVarreni wivfgseiiz; Q

fi lfhe Union fiyvitch and Signa y, Swissacorporation.ofliennsylvaiiiarippii aaon'-septiater s, rang-serial Newman 9 Claims.

Myinvention'relates to railway :trafiic controlling apparatus, and moreparticularlyxtoctrafiic direction lockingiapparatus for the control oftraffic :movements between :two blo'ckxstations or interlocking plantson 5-2, multiple 'tracktrailroad.

.One object of my invention is ttoiipreventithe operator at either oftwot'stations .conn'ectedby a plurality of tracks fromclearinganyxsignal which governs traffic movements into any routeleading to the other "station unless the corresponding trafiic directionfor traffic movements in that route has 'been setiupzby the joint:action of the operators at'the two "stations.

Another object of my invention is theprovision of:a unitary setof'trafficdirection lockingiiapparatus of this characterfor controllingthe direc-.

tionoftrafiic movements over each of-a plurality ofstretches oitrackextending betweentwo-stations, which is controllable overasihgle pairpfline wires, such as atelephone linetconnecting thestations, by means of:distinctive codeisignals or impulses ofdifferent characters.

. In its specific embodiment as' shownfherein, the apparatus ofmyinvention a includesla :two

position tralfic lever, apush button, and: atraffic relay-of the stickpolar rtype at each ofzthe two stations,=for each stretch of'itrackconnecting the stations, togetherwith suitable selecting. -apparatus bymeans of which 'each" of the: traflic relays may beoperated'toaip'ositi'on correspond- -ing to that of the associatedtrafiiclever by'a distinctive code signal transmittedaoverthe'slinewires, when the push button 'atthe othertstation for the correspondingstretch of track is operated.

Each 'trafiic relay in one position "designatesithe adjacent end of thecorresponding-stretchasz'the entrance end, and closes acontactinzthe'circuits for the signals at that .end whichgovern trafiicmovements into the stretch. "Ihecorresponding trafiic relay at'the-otherend of that :stretchof .track in a similar position designates-its endas the exit end. of the stretch; and in thistposition the relay closes acontactinthe circuit govern-ed by the associated push button by means ofwhich the first mentioned relay maybe operated: by: its

'lever under suitable trafiicmdirections in order to reversethedirection of traflic. g

I shall describe one form ofsapparatus embodyingmy invention and shallthenflpoint out the novel features thereof'in claims.

In the accompanying drawings, Figs. ylAuand 1B, 1 taken together,illustrate the trafiic locking 1 apparatusofmy inventi'on'as appliedtothe conv:trol over apair ofeline wires Y andzofithe traf- (01346 .134).fice;directionioneachcofr the four. tracks of. a :fourtra k 'r m c g UThe-territory controlled by one set=of this apparatusrissito'be understod to-bethat shown in i :5 the ra kin an whi -extend a ro s t p eportions of- 1?igs. 1A; and 1B,;eomprising the tracks 10f two'interlockingplants at locations identified-as fstation N0. g l andfistation No; 2, respectively, .w etherj 'iwith the intervening .10'stretch.i-;cornprising the nain gtraeks i IT, 2 2T, 3T, 'and'AT.The-twointerlocking plants are-assumed IO-be similar, -.ea c h.including :enseries of crossover switchesidentifiedibvfihgnumber 1,- 3,5 '7, '9,-*and :11. to ether iwith;-,a- ;-plurality of signals r llimforgoverningtraflic'movements in both directions overath-e E routes -,forined by .the j switches.

Fig-i2 ShOWS CiI'GIHtS whichmay be employed atszea'chzinterlockingplantitogovern the mecha .nismsfor, the: s-ignals:-.at;that; plant; Thesignals ZO-Jare identified by the-tnu nbers re, 6, .8, and 10,

with-.a ,suflix R -or.=L to indicate that the direcxtiontofztrafiicmovement governed thereby is to- 'Ward,therrightiori'left. irespeetively, while the operatingmechanisms;forithe signals are. identi-25 =fied by the reference; character G following thegsignal'rdesignations. i'llhe circuitsl's'hown in Fig. 2 :arefad-apted'for use at an interlocking plant locatedpat a ."s tation where:the signals governing tnafliczmoyements in bothdirections are con- :30,trolled rby: .traflic locking -appa-ratus of the type -shown iniFigs.IA;BI1(1;1B. A U y *W-hen :but i 0118 5581, of trafliclocking apparatusliszto beyconsidered. this isarranged as shownby placin .Fig.,.-1Aat*theleft of i Fig. 1B and by emi- :ployingcircuits shown;in Fig.2 at thestations "at'iboth ends ofythestretch. ln this arrangement, theflsignalcircuits at. station No. -1, Fig. 1A, are 1 those :for vthe;signals Rin, Fig.2, which include contacts gof atheztrafiic relays *IF R,4FR ofFig. .40 1A, while .the signal circuits at stationNo, 2, Fig.-1l3,uare\thoseifo r thetsignals L in-Fig. 2 vvhich include contacts 10fthe tralfic relays IFL AFL eti -i B It-will-be understood that othersets of trafiic 4 locking apparatus similar to the one shown .in .-Figs.1A and l-B may -be us ed to control trafiic .,moveinent s:in= theistretches ,atthe left of station No.. 1 and at the; 'ght of station No,2, in which case the; tramq loclging apparatus at each inter- 50mediatestationiwifl includethat of both Figs. 1A and .il-B; controlledrover L line wires" extending in ,opposite directions, as ,vvell as.that of Fig. 2 in V henithelcircuits for the ,z i a ;f ri eih g t ei eni -e b ;5owtrclledrby trafiicrelays :l fRriandFL it is to be understoodthat these relays belong to different sets of the traffic lockingapparatus of Figs. 1A and 13.

Similar reference characters refer to similar parts in each of theviews, and to simplify the drawings, in lieu of showing the localsources of current for energizing the various relays, I have shown onlytheir terminals, the reference character 3 identifying the positive orsupply terminal and C the negative or common return terminal, in eachinstance.

Referring to Fig. 2, each station is assumed to contain an interlockingmachineof the conventional locked lever type for the local control ofthe switches and signals at that station, suchforexample, as is shownand described'in the book' Electro-Pneumatic Interlocking, publishedNovember 1914, by The Union Switch and Signal Company, Swissvale, Pa.For an understanding of my invention it is deemed suincient to point outthat the interlocking machine at each station includes a two positionswitch lever SW for each single switch or crossover, such as the leverISW 'for the crossover switches I, for example, to

which is attached a multiple contact circuit controller. As indicateddiagrammatically by a dotted line connection in Fig.2, contact a of theswitch lever ISW controls circuits for governing the power operation ofthe crossover switches 1 so that the switches have assumed their normalposition as shown when lever ISW occupies its normal or left-handposition, and have assumed their reverse position as required for atrain movement from one main track-to'another when the switch lever isreversed.

switch controls the usual switch-indication relay such as the relay lWP,which reflects the position of both switches of the crossover and itscontacts jointly with contacts of the associated switch lever such asthe contacts I) and c of relay ISW' are included in route circuits 'overwhich the signals which govern traflic movements over that crossover arecontrolled. Each switch lever at station No. 1 has additional contactssuch as the contacts e, 1 and g of lever ISW shownin Fig. 1A includedinalocking circuit network for controlling the trafiic relays FR, while atstation No. 2, other switch lever contacts, such as the contacts h, a,k, and 'm of the lever ISW at that station are included in a similar butoppositely directed locking circuit network for controlling the trafficrelays FL. Each signal is provided with an operating mechanism shown 'inFigure 2am identified by the reference character G prefixed by thedesignation of the signal as marked on the track diagram, such as themechanisms IBRAG and IEiLG for signals IDEA and IL, respectively, theclearing of each signal being effected by energizing its mechanism overa route circuit in Fig.

2 established by the switch levers SW and indication relays WP. Eachroute circuit for a signal which governs traffic movements towardanother interlocking plant connected by the direction locking apparatusof my invention, also includes a contact d of a traffic relay FR or FLas shown. Each group of signals bearing the same numerical prefix isgoverned by a circuit controller atv tached to a correspondinglynumbered three position signal lever SG. Each signal lever, such aslever IBSG, for example, normally standsin a center position as shown,from which it 'maybe operated to the right to energize the signalmechanism l I] RAG or IBRBG by completing a circuit over the right-:handlever contact a, or it may be operated to the left to energize mechanismEach crossover IIJLG for the opposing signal IBL by completing IUSG.

The circuit for signal IGRA at station No. 1, for example, extends fromterminal B at contact 01 of relay IFR over contact b of lever IUSG,normal contact 0 of lever ISW, the neutral and normal polar contacts ofrelays IWP and WP, normal contact 0 of lever l ISW, right hand contact aof lever IBSG, contact (1 of lever ll SW and a front contact of thetrack relay HTR for section HT and thence through the winding ofmechanism IURAG to terminal 0.

Each signal lever at station No. 1 has additional contacts such as thecontacts 0, d, e and f of lever IOSG, in the locking circuits for therelays FR in Fig. 1A, while at station No. 2, the corresponding signallever has other contacts such as contacts g, h, :i and k of lever IUSG,shown in Fig. 1B, in the locking circuits for the relays FL.

It will be understood that the switch and signal levers are interlockedmechanically and also electrically, at times, by means of lock magnetsin the conventional manner as described in the book referred to, andthat the positions of the switches and signals are indicated by thepositions of their respective levers. That is to say, the lock magnetfor each switch lever prevents its movement to the full normal positionas shown herein except when the switches controlled thereby are. lockedin their normal position, and the lock magnet for each signal leverprevents its return to the normal position as shown except when allof'the signals controlled by such lever stand at stop.

Referring now to Figs. 1A and 1B, the trafiic locking apparatus atstation No. 1 includes a line battery Bl, a code transmiter IBGCT forinterrupting the current delivered by battery Bl at the rate of 180times per minute, and a set of four push buttons IRE-4R3, one for eachof the four tracks |T4T, by means of which current of one of fourdistinctive characters, positive or negative, steady or interrupted, maybe supplied from battery Bl to the line wires Y and. Z to permit thecorresponding one of the four traffic relays IFL4FL at station No. 2, atthe right, to be operated to a position determined by that of thecorresponding one of the four traffic levers lVIr-WL, provided firstthat the block telephones T which are normally connected to the linewires Y and Z are disconnected therefrom by the operation of keys KI andK2. StationNo, 2 is provided with a similar line battery B2 and codetransmitter IBIJCT, and with a set of four push buttons |LB4LB forsupplying positive or negative, steady or interrupted current frombattery B2 to the line wires Y and Z extending to the left, toselectively control the traffic relays Im- 4FR at station No. 1, inaccordance with the positions of levers IVE-WE. The decoding apparatusby which the traffic relays are rendered selectively responsive to thecurrents of different character is similar at the two stations, and byreference to Fig. 1A it will be seen that this includes a polar stickrelay PI and a biased polar relay RI, which by the operation of key Kl,are connected in series across line wires Y and Z over the normallyclosed contacts of each of the push buttons IRE-4R3. These relaysfunction like the similar relays shown in Letters Patent of the UnitedStates No.'2,324,200, issued July I3, 1943, to A. E. Dodd, that is, whenwire Y is positive, relay Pl closes its lefthand contact a from left toright through relay RI and rectifier [2 to wire Z to f 'r ayRl'aridsupliedjtoa codeedetectorrelay DI,

bohtidh. Rliy SDI 'i'emaifisiD itSTIEasedpO- sition when relay BI .ispperatedperiodicahy as bed,,and'therefo elisselectively responsive"toist "ady eurrentjre j ive overwires'y z.

er the relays I uit fificludinghontact a of the corresponding "lever IYVR' 4VR, and a distinctive combinl ationof the conta'c ofielay' l, CD!and SDI, layfli'Rjalso,includingfone as "shown 1 inQlHdsj contacts ofthe gnal'leversofFi i 2. Assuming that rje'Yf' gative, relay "iflRisienergized'if inter. ed ur'reht is supplied and relayZFR'iseneradyeur'rene' is. supplied from jstation Whenjewi'teQY isfpo's itive, relayfllli'. is i gized if interruptedburrent ,is supplied "and 1 r m e nN -a.n a n mu fais be seen tliat iw'hen one "of the ed with thetiafficievers'is V s 'forfcohtrolling'the asso- "traifiic, reIaYsQare opened, and ifthe corresponding trafiio' relay andlever are both inthe'ireiiitepositions'lthis being theleit h-andlposition n-Eig. 111A and T1the right ha-nd position in Fig. 13)," ourifn t is supplied m me Wires,Y-Z over ewhioh is ofjthie same character as that by which suchl relayis goyerned, to operate the corresponding relay FL or PR at the otherstation. In other words, thecode signals have different charactersjfwhichjidentify the trafiic locking apparatus for the difierent tracks,and each setof apparatus ,e ploys code signals nof the characterassigned theret'o, for both directions of transmission.

The -locking circuit networks shown in Figs 1A manually to stop by theoperation of any lever fa out} onefsecon'd beiore it assumes itsenergized is controlled over it bertion ine; locking'circuit net hayenergized if "steady current is 'sup- 75 1ad'ing' into section nan-5.;

l n t cuitbra rlay responsive to t p n ha en 1' i -is atTstopjthecircuitior J ayjfFRfmaybe closed fo er th c rcuit lbianoh inchidingfon'tact .jof lever IS W and contact-c of lever] I HSG. Second, when" crossover lIis re erse crossover I 'is'fnornial, allero ut jnqiii to section IIare'bdtfoked, IeVer- I'QSG S A 4 tolthe'right-to' clea sign-e1initiators Iihto section 2T, land! the circuit "if or" rela PER 30maybeclosed'ioverlthe rc'uit contacts e of '1 v rsi'sjw and cros'soveril' is "r evei's'edgafid c normal, signer an is th i'enteroutei'includingse "ion II; V iiial and signal" 10m; is ""th filtering?signal if crossover-II is reverse In e1therfcasefif the A signal levers8G and 10S, "in" their "normal orlleft h'an'd positions, "t frela'yllFRmay be "closed evergth l: ir contact dlofl leveii, sswa ssor eiidfms'or.iFQuith, w en 3 are reversed, a iossov Vere l and I l Q9 rid 5 arenormal, signal ERbcomesTtheefit fi lsignalflfor the route includingsection I T an if this signal is 'at stop and levers "6S 8n'df'lflSGjare in theirnormal or lefti-ha d i" m y be energized ever qing contact e of lever" 557W levers a se, SSGf'a'fid ave s l', 3 emigre1 normal, signal dRj'beco the route including seen is at stop landlevers 4S are allvinv thirhorrrial 55 relay IFER. may Ibefe v branchincluding contacts levers. .e p

The locking circuits'iorjeabhfif the relays 2FR, FR and amiiurfietierggi tgenereuy similar 0 mannenland it 'istherefor emed'unneces- 3 sa ryzto trace "thesefcirolliits met ail. ;In each case thelookingv'vcircuits server place the traffic relay under thelcontr'o oftheflever for the particular signal which f rns' tiafiic movementsintothe route-leading toethat one of the sections IT"4T with whichsuchtrafiic-re1ay is associated. M I a v 1 l l In'Fig. 1B,equivalentlockfingj circuits are provided for each of the trlfilc relayslFL 'lI' L, hrranged for the opposite direction of 'traffio-movements asrequired forthe various'routes at station No. 2-w hich-le ad intosection'sT'I J T. For example, when switches I and II are normaI,signal; I'OL is} the enterin {'si nalfior he 1 route "IT if the signallever and: if this signal tsq'isso" and IUSGY litihan d "positions, edover the f circuit 0" of "each of' these brevehtmgthe jree to; be,operated IHSG at station No. 2 is in its normal or righthand positionindicating thatjthis signal is at stop, relay IFL may be energized overthe circuit'branch including contact In of lever IISW and contact g oflever IIJSG. Each of the lockink circuits in Fig. 1A has its counterpartinrFig. 1B, the circuit branch just traced, for example, correspondingto the one in, Fig. 1A which includes contact 1 of lever ISW and contactof lever IIISG, and in view of the similarity of these circuits to thoseof Fig. 1A it is believed that they will be readily understood from thedrawings without further description.

The purpose of the trafiic relays is to prevent either operator fromclearing a signal for a route leading into anyone of the sections IT-flTin a'direction contrary to that agreed upon. Considering the lower maintrack, for example, the trafiic relays IFR and IFL normally both havetheir right-hand contacts closed designating the direction from left toright for movements over the stretch IT, this being indicated at stationNo. 1 by the lighting of a directional indicator lamp IRE over anobvious circuit, the corresponding lamp ILE at station No. 2 being dark.At station No. 1, contact d of relay FR, shown in Fig. 2, is closed toconnect terminal B to the circuit for the signal 4R, 6R, 8R3 or 4RA,dependent upon the position of the track switches, which governs traflicmovements into stretch IT. Thus with switch levers IISW and ISW normal,as shown, by moving lever IUSG to the right to close its right-handcontact a, a circuit is closed through mechanism IIIRAG to terminal C toclear signal IRA, as may readily be traced from the drawing.

opening of its contact a extinguishes station No. 1, after havingoperated relay At station No. 2, contact 11 of relay IFL is open. Thisprevents the clearing of that signal which governs trafiic movements inthe againsttrafiic direction into stretch IT, if the operator at thatstation should inadvertently operate the signal lever therefor to itsleft-hand position. Thus, for example, if crossovers Nos. I and II atstation No. 2 are normal, mechanism IOLG does not become energized inresponse to the closing of left-hand contact b of lever II'ISG becauseterminal B is disconnected from the circuit by contact (1 ofrelay IFL.When one or more of the crossovers is reversed, contact d of relay IFLopens the circuit for signal ALB, ELB or 8L according to the route whichleads to stretch IT, as shown by Fig 2.

I shall now describe the operation of the traflic locking apparatus ofmy invention, starting with the assumption that the apparatus is in itsnormal condition as'shown and that it is desired to reverse traffic instretch IT. The operators reverse the keys KI and K2 to establish abattery circuit over the line wires Y and Z.

The operator at station No. 1 then places lever IVR in its left-handposition while the operator at station No; 2 presses button ILB for abrief interval corresponding to several cycles of operation of relayIBUCT at that station, thereby supplying interrupted current of negativepolarity to the line. The line circuit thereby established extends fromthe positive terminal of battery B2 over the contact of I80CT, Fig. 13,contacts 0 of relay IFL and of lever IVL, contacts of keys ILB and K2 toline Z, thence in Fig. 1A over contacts of keys KI, IRB, 2RB, 3RB, andIRB, rectifier I3, contact a and winding of relay PI, contacts of keys4RB to IE3 and of lrey KI to line Y, thence in Fig. 13 over contacts ofkeys K2 and .ILB, contactsb of lever IVLand Relay PI is caused to relayIFL to the negative terminal of battery B2.- assume' its reverseposition, whereupon relay RI responds periodicallyto ,ef-- feet theselective energizationof relay CDI, closing a circuitfrom' terminal 13at the right-hand contact I; of relay PI over back contact I of relaySDI, contact d of relay CDI, contact of lever ISW, contact 0 of leverIOSG, the left-hand contact a' of lever IVR through the lower winding ofrelay IFR to terminal C, thereby causing relay IFR to operate itscontacts to the left-f The lamp IRE and the opening ofits contact d,Fig; 2, disconnects terminal B from the circuits for the signals atstation No. 1 which govern traflic movements into section IT. j V jSince contacts b and c of both the trailic relays IFR and IFL are nowclosed, either direction of traffic may now be established, as desired.

To restore the original direction, the operator at station No. 1operates lever LVR to the right and the operator at station'No. 2 againpresses button ILB to againsupply interrupted current of negativepolarity to the line, whereupon relay IFR operates its contacts to theright and so assumes its original position corresponding to that ofrelay IFL.

To reverse the trafiic direction, the operator at to the left as abovedescribed, presses button IRB while the operator at station No. 2operates lever IVL to the left. Interrupted current of negative polarityis now supplied'to the line from battery BI, Fig.'1A, over a circuitsimilar to that already traced, and distinctive code signal receivedover line wires Y and Z from station No. 1 causes relay P2 to i assumeits reverse position, and relay R2 operates periodically to cause theselective energization of relay CD2. If the looking conditions atstation No.2 are proper, the closing of conta'ct'd of relay CD2completes a circuit for relay IFL, such as the one extending fromterminal B at the right'hand lower contact of relay P2, back contact bofrelay SD2 and front contact d of relay CD2, and includingcontact g oflever IIISG and contact is of lever IISW, for example, and the left-handcontact a of lever IVL, so that relay IFL closes its left-hand contactsand so assumes a position corresponding to that of relay IFR. Theclosing of contact a of relay IFL lights the directional indication lampILE, and the closing of its contact at, Fig. 2, prepares a circuit forthe mechanism IIlLG for signal IUL, at station No.2for example, whichgoverns traflic movements over the established route leading to sectionIT. The opening of fcontacts b and c of relay IFL maintains relay IFRdeenergized in the corresponding left-hand position. V e 1 It will benoted that the traffic relays'being normally deenergized, are locked intheir entrance positions as well as in their exit'positions, so thattheoperator who has control of trafllc movements is able to change theposition of his traific relay to give up that control only bycooperation with the operator at the other station under conditions suchthat his control may be reestablished, if desired. It follows that ifdue to a fault or to locking conditions at one of the stations, theoperators are unable to'complete the operations for reversing thedirection of traffic they will generally be able to restore the originaldirection and thereby avoid a locked condition rendering the stretchunavailable for trafiic movementsin eitherdirection I r a 1 IFR It willalso be noted that the operation of reversing trafiic," conditions-ias'described; involves, a check SdIL-th'e locking conditions oat; bothstations; and that' theseloiieratio'rismn'st beiniti'atedbytheparentthatthoseinvolving stretch 2'Ilare similar,

difiering'jonly, the" character. of line r'current,

steady negative current'being supplied to the line, by the cpration er'button 'ZLB or; ZRB to selece tivly operate the sl'owpick-up relays'SDin place: on. Likewise. those.

of 'th'e co'd detector'jrelays involvi gtl'ie stretches3T a'nd 4Tdifferv only'fin th" plied to thence so that r the lieir"norinalpositions SD areoperatgus Nthugh I ha've herein only-6513mm of railwaytraiiiccontrolling 'ap-' paratus "einbodying 'n'iyfinvention," it isunder s'too that" various changes and modifications relays P'lior P2appended nsane *w'ithout'departing from the sbiiiitand'scop ofni'yinvention Tia-yin describedi 'm y "invention, What I 01a v o flcdirection locking apparatus for a stretch of musty track having'a'signal at each nd f r governing tranidmo ements' into said tr et; was

relayoff thestick-polar type at each end of the already established'direction on traffic, in) each the; control intnuptedor steadypositivecurrent is s'upwhen relays 'or.

shown and described may e made therein within the scope of theconnectingl sa d statio s,--a-= cal; circuit non traffic lever and "a".tram-c n all yscl bsld said stretch, a two positig'n traffic lever, apush ton andiatraiil rela of thestick polar. type for each. oii-saidftr'at aminence: cl t ii xien nsi he n t i the stretch iludirigFselectinginieansl aiidnort e s ises: P t i the selectingjnieansat each hen opeifatcd for completin of its; two. positions for"actuatingthe selecting means at the opposite end-of the stretch to complate the circuits for the-trams relay for the, cor-;

responding track at -said iopbpsit en d f the stretch, and m anscontroliedeach traflic re-i lay inthe other ot-itsitworpositions for.clearing 4; Traflic, directiqn, locking apparatus for the control 3 oftrafiic movements lover, a, plurality of stretchfa circuitcoritrolledbyeach'traffic lever for operating the associated ma between"its no mal "and reverse positions, the circuit for'one in tion be n aontr l a o t othert fafiic relay closed in "its revrsepose a 'd' thecircuitdor said other trafiic rel'a'y controlled afcontact of said: onetraffi'c closed in itsho'rrn'al positionfa" circuit ear n g 'one -s ignal; controlled by 7 acdnttct of ne trailic clay "closed only" in its i 1"=velrse n, and a' circuit for clearing the other sig-f na qi tit ed riece ia fth t r am? lai 'c cs dcnlir. n tsn mel pb iiij nf "2 "Ijraflic"direction locking apparatus for a stretchfo f; ailwa'y track hayinig asignal "at each v mg traflic 'movementsdnto said Gite t pp it en ame vt' i ii sh ii t a traffiic r ayofthe, sticl; polar type at each of, thestretcl1;"l ine wires extending the thf'ofsaid ea hfa circuit controlledby tra fic relay between" its normal and reverse posi ti'o'nsi" meansincluding "said linef wires for nergiz ing thejcircuit. foreach' traificrelay in 'respon's'e to the "operation of the push button at control oftrafiicmovem'ents e lf'traffi lever for, operating ll?)associated theopposite end of the stretch, the circuit for ciliii itro lled by acontact of the other trafiic relay stretchesofa railway trachextending:betweentwo" stations, comprising; an t twoaposition traific lever, atractiic relayof- 'the stick-polan-type, and-t a' push;:button atxeachstation;- two linewires,

trolled byreach-leverefonjoperating the associated relay betweenits-normal? and reverse positions, selecting; means} at "each stationconnected to said line wires overmnorm l yo ed co t c s ofr'eacli' otthepush buttons-"atxthat station, means .controlled. by said selec means foselectively completing said: local; circuits only one at a time .eachresponse to; a distinctive code signal received over; said linewires,'a1nd means at each-station for; supplying such code; signalstothe line wires in response to; the operation or the push buttons "at-:that station the operation cf ea'ch such"button .being'efiective onlywhen the associated traific relayi and-- lever occupy a particular one:of their; two positions to supply that code signal to the line? wires bywhich; the

'trafficielay atthe other station for the same stretch of trackisqselecteds 5; Traffic direction locking apparatus for the :oyeraplurality of stretches of railway? track extending between twostationscomprising', 'a trafl'ic locking contact at eachstation'foreach' of saidstretches each of which is adapted to be lockedin an open position in' which it prevents the movement-of traffic i intoits stretch from the' adjacentend, a trafiic lever for each such contactfor controlling its operation,- a push button for each lever, two linewires connecting said stationspselecting means at each stationconnected-"to said line wires. over normally closd 'contacts'ofeachf'iof: the push buttons at at that station, rneans controlled bysaid selecting means for: selectively "rendering the trafiic lookingcontacts operable byf their: respective levers only one at atim'eeachlin response to a; distinctiveco d e' signal 'received oversaid line wires, and meanest each". station Cfor-supplying such codesignals to thel i'ne wires in response to the operation of the push"buttons at that station the epemuonfoieachpush button being effectiveto controlthe traffic locking contact at, the other station for a "givenstretch of? track only when tli one i at the same .2 station for thatstretch is its lopenipositionis: I

await eiidifthefstiietch; v

b ac er tiblf e a h' -bi li fi n the r the associated trafificrelayioc'cupies alpariticular one ing a manually o-perable 6. Trafficdirectionlocking apparatus for the control of traff c movements over aplurality of stretches of railway track extending between two stationscomprising, a traffic loc'ldng contact at each station for each otsaidstretches each of which is adapted lto be locked in an open position themovement of traffic into e adjacent end, a tr'aflic lever for each suchcontact for controlling its operation, a push button foreach lever, twolinewires connecting said stations, means at each station fortransmitting a different code signal over said line wires to the otherstation in response to the operation of each of said push buttons, eachpush button being efiective to transmit its signal only when theassociated name looking contact is locked in its open position, andselecting means at each station responsive to each such codesignaltransmitted from the other station for rendering the traflic lockingcontact for the corresponding one of said stretches of track free to beoperated to its open or closed position by its lever.

'7. Traffic direction locking apparatus for a plurality of stretches ofrailway track extending between two stations, at each of which signalsare provided for governing traffic movements over various routes,established by the operation Of track switches which include one oranother of said stretches; comprising, a traffic locking contact at eachstation for each stretch, each of which is adapted to be locked in anopen position in which it prevents the clearing of the signal at thatstation governing traffic movements over any route including itsstretch, a manually operable lever for each traflic locking contact forcontrolling its operation, a push button for each lever, two line wiresconnecting said stations, means at each station for transmittingdifferently coded impulses over said line wires to the other station,each in response to the operation of a different one of said pushbuttons, each push button being effective to transmit its impulse onlywhen the associated traffic locking contact is locked in its openposition, selecting means at each station controlled over said linewires and over normally closed contacts of the push buttons at the samestation in response to said impulses,

a trafiic locking circuitfor each stretch closed by said selecting meansin response to an impulse identifying the corresponding stretch eachsuch circuit when closed rendering the associated trafiic lockingcontact free to be operated to its open or closed position by its lever,and locking means at each station'effective to prevent the closing ofthe traffic locking circuit for any stretch by said selecting means whena signal at the same station has been cleared fora route which includesthat stretch.

8. Traffic direction locking apparatus for a plurality of stretches ofrailway track extending between two stations, at each of which signalsare provided for governing trafiic movements over different routesestablished by the operation of track switches, each. route includingone or another of said stretches; comprising, a traflic lockingcontactat each station for each stretch havlever effective at times to operatethe contact to its open or closed position, a push button associatedtherewith, a reversible line circuit connecting said stations connectednormally to selecting means over normally closed contacts of the pushbuttons at each station, means at each station ently coded impulses oversaid line circuit in re- 12 sponse to the operation of said push buttonseach push button being effective to transmit a distinctive impulseidentifying the corresponding stretch of track only when the associatedtraf- 1'10 locking contact is in its open position, a local .trafficlocking circuit at each station for each stretch closed by saidselecting means in response to an impulse identifying the correspondingstretch of trackeach such circuit when closed rendering the associatedtraffic locking contact freeto be operated to its open or closedposition by its lever, means controlled in accordance with the positionsof the track switches at each station for preventing the closing of thetraflic locking circuit for any stretch by said se lecting means when asignal at the same station has been cleared for a route which includesthat stretch, and means controlled by each trafiic lockingcontact inaccordance with the-position of the track switches for preventing theclearing of that signal which governs traffic movements over theroutewhich includes the corresponding stretch except when such contactis closed.

9. Traffic direction locking apparatus for the control of trafficmovements over a plurality of stretches of railway track extendingbetween two stations; a traffic locking relay at each station for eachstretch each such relay having an entrance and an exit position, amanually operable buttons at each end,

- trolled by each push lever and a push button for each trafiic lockingrelay, a reversible line circuit connecting said stations normallyconnected to a polarized line relay over normally closed contacts of thepush means at each station including normally open contacts of the pushbuttons for transmitting difierently coded impulses over said linecircuit to control the line relay at the other station, the transmittingcircuit conbutton including a source of current and a contact of theassociated trafiic locking relay closed in-its exit position, selectingmeans controlled by each line relay adapted to close different selectingcontacts in response to impulses identifying the different push buttonsat the other station, a circuit for operating-each traffic relay to itsentrance or exit position in ac cordance with'the position of its leverincluding the corresponding selecting contacts and also in- 1 eludinglocking contacts closed in accordance with trafilc conditions only whenit is proper to direct trafiic toward the station over the correspondingstretch oftrack, means at each station for pre venting the movement oftraffic from that station into any of said stretches except when thecorresponding traffic relay occupies its exit position, and an indicatorat each station for each stretch arranged to visually indicate theposition, of the corresponding traflic relay.

. WARREN W. SEITZ.

nEFEnENcEs CITED The following references are of record in" the file ofthis patent:

for transmitting difier- UNITED STATES PATENTS I Number Name Date1,102,861 Bliss July '1, 1914 1,998,178 Wallace Apr. 16, 1935 2,121,785Bushnell June 28, 1938 2,149,222 Langdon .Feb.'28, 1939 2,249,097Vanhorn July 15,1 41

- 2,354,023 Ihrig July 18, 1944 .Failor 1 Jan. 9, 194,5

